Fans of
"Doctor Who" are using the 50th anniversary celebration for a worthwhile cause. "Doctor Who Fans Against Cancer" is raising money for Unite Against Cancer, a charitable organization in Scotland, home of the 10th and 12th Doctors (
David Tennant and
Peter Capaldi).

The fundraiser is looking to raise 10,000 pounds ($16,130) by November 23, when the 50th anniversary special, "The Day of the Doctor," airs. The money raised will be used to fund research of new cancer treatments.

The special features the return of Tennant in his role of the Doctor, as he teams with
Matt Smith. The episode will also be Smith's penultimate appearance on the show, as he regenerates in the annual Christmas special, when Capaldi takes over the role.